Shuttle Endeavour’s Final Journey

IN SPACE - MAY 18: In this handout provided by National Aeronautics and Space Administration (NASA), NASA space shuttle Endeavour begins the nine-minute Rendezvous Pitch Maneuver, or 'backflip,' in order to be photographed then dock on its last visit to the International Space Station on May 18, 2011 in space. After 20 years, 25 missions and more than 115 million miles in space, Endeavour is on its final flight to the International Space Station before being retired and donated to the California Science Center in Los Angeles. Capt. Mark E. Kelly, Gabrielle Giffords's husband, will lead mission STS-134 as it delivers the Express Logistics Carrier-3 (ELC-3) and the Alpha Magnetic Spectrometer (AMS-2) to the International Space Station. (Photo by NASA via Getty Images)

IN SPACE - MAY 18: In this handout screen grab provided by the European Space Agency (ESA), NASA space shuttle Endeavour approaches for docking the International Space Station on May 18, 2011 in space. After 20 years, 25 missions and more than 115 million miles in space, Endeavour is on its final flight to the International Space Station before being retired and donated to the California Science Center in Los Angeles. Capt. Mark E. Kelly, U.S. Sen. Gabrielle Giffords's husband, will lead mission STS-134 as it delivers the Express Logistics Carrier-3 (ELC-3) and the Alpha Magnetic Spectrometer (AMS-2) to the International Space Station. (Photo by ESA via Getty Images)

IN SPACE - MAY 19: In this handout provided by National Aeronautics and Space Administration (NASA), NASA space shuttle Endeavour starboard wing prior to docking to the International Space Station on May 19, 2011 in space. After 20 years, 25 missions and more than 115 million miles in space, Endeavour is on its final flight to the International Space Station before being retired and donated to the California Science Center in Los Angeles. Capt. Mark E. Kelly, U.S. Rep. Gabrielle Giffords' (D-AZ) husband, will lead mission STS-134 as it delivers the Express Logistics Carrier-3 (ELC-3) and the Alpha Magnetic Spectrometer (AMS-2) to the International Space Station. (Photo by NASA via Getty Images)

IN SPACE - MAY 19: In this handout provided by National Aeronautics and Space Administration (NASA), NASA space shuttle Endeavour docks to the International Space Station on May 19, 2011 in space. After 20 years, 25 missions and more than 115 million miles in space, Endeavour is on its final flight to the International Space Station before being retired and donated to the California Science Center in Los Angeles. Capt. Mark E. Kelly, U.S. Rep. Gabrielle Giffords' (D-AZ) husband, will lead mission STS-134 as it delivers the Express Logistics Carrier-3 (ELC-3) and the Alpha Magnetic Spectrometer (AMS-2) to the International Space Station. (Photo by NASA via Getty Images)

IN SPACE - MAY 22: In this handout provided by National Aeronautics and Space Administration (NASA), Astronaut Andrew Feustel reenters the space station after completing n 8-hour, 7-minute spacewalk at 10:12 a.m. EDT as NASA space shuttle Endeavour makes its last visit to the International Space Station on May 22, 2011 in space. After 20 years, 25 missions and more than 115 million miles in space, Endeavour is on its final flight to the International Space Station before being retired and donated to the California Science Center in Los Angeles. Capt. Mark E. Kelly, U.S. Rep. Gabrielle Giffords' (D-AZ) husband, will lead mission STS-134 as it delivers the Express Logistics Carrier-3 (ELC-3) and the Alpha Magnetic Spectrometer (AMS-2) to the International Space Station. (Photo by NASA via Getty Images)

IN SPACE - MAY 21: In this handout provided by National Aeronautics and Space Administration (NASA), the newly-installed Alpha Magnetic Spectrometer-2 is visible at center of the International Space Station's starboard truss as NASA space shuttle Endeavour makes its last visit to the International Space Station on May 21, 2011 in space. After 20 years, 25 missions and more than 115 million miles in space, Endeavour is on its final flight to the International Space Station before being retired and donated to the California Science Center in Los Angeles. Capt. Mark E. Kelly, U.S. Rep. Gabrielle Giffords' (D-AZ) husband, will lead mission STS-134 as it delivers the Express Logistics Carrier-3 (ELC-3) and the Alpha Magnetic Spectrometer (AMS-2) to the International Space Station. (Photo by NASA via Getty Images)

IN SPACE - MAY 20: In this handout provided by National Aeronautics and Space Administration (NASA), Astronaut Drew Feustel works in the vacuum of space during the first of four spacewalks during the STS-134 mission of NASA Space Shuttle Endeavour to the International Space Station on May 20, 2011 in space. After 20 years, 25 missions and more than 115 million miles in space, Endeavour is on its final flight to the International Space Station before being retired and donated to the California Science Center in Los Angeles. Capt. Mark E. Kelly, U.S. Rep. Gabrielle Giffords' (D-AZ) husband, will lead mission STS-134 as it delivers the Express Logistics Carrier-3 (ELC-3) and the Alpha Magnetic Spectrometer (AMS-2) to the International Space Station. (Photo by NASA via Getty Images)

IN SPACE - MAY 20: In this handout provided by National Aeronautics and Space Administration (NASA), International Space Station solar array wings intersect the thin line of Earth's atmosphere photographed by an STS-134 crew member while space shuttle Endeavour remained docked with the station May 20, 2011 in space. After 20 years, 25 missions and more than 115 million miles in space, NASA space shuttle Endeavour is on its final flight to the International Space Station before being retired and donated to the California Science Center in Los Angeles. Capt. Mark E. Kelly, U.S. Rep. Gabrielle Giffords' (D-AZ) husband, will lead mission STS-134 as it delivers the Express Logistics Carrier-3 (ELC-3) and the Alpha Magnetic Spectrometer (AMS-2) to the International Space Station. (Photo by NASA via Getty Images)

IN SPACE - MAY 25: In this handout provided by National Aeronautics and Space Administration (NASA), with components of the International Space Station in the view, the forward section of NASA space shuttle Endeavour is seen with two components of the International Space Station (ISS); the Harmony node (left) and the European Space Agency's Columbus laboratory May 25, 2011 in space. After 20 years, 25 missions and more than 115 million miles in space, Endeavour is on its final flight to the International Space Station before being retired and donated to the California Science Center in Los Angeles. Capt. Mark E. Kelly, U.S. Rep. Gabrielle Giffords' (D-AZ) husband, will lead mission STS-134 as it delivers the Express Logistics Carrier-3 (ELC-3) and the Alpha Magnetic Spectrometer (AMS-2) to the International Space Station. (Photo by NASA via Getty Images)

IN SPACE - MAY 28: In this handout provided by National Aeronautics and Space Administration (NASA), NASA astronaut Michael Fincke, STS-134 mission specialist, performs maintenance on the Carbon Dioxide Removal Assembly in the Kibo laboratory of the International Space Station while space shuttle Endeavour remains docked with the station May 28, 2011 in space. After 20 years, 25 missions and more than 115 million miles in space, NASA space shuttle Endeavour is on its final flight to the International Space Station before being retired and donated to the California Science Center in Los Angeles. Capt. Mark E. Kelly, U.S. Rep. Gabrielle Giffords' (D-AZ) husband, will lead mission STS-134 as it delivers the Express Logistics Carrier-3 (ELC-3) and the Alpha Magnetic Spectrometer (AMS-2) to the International Space Station. (Photo by NASA via Getty Images)

IN SPACE - MAY 25: In this handout provided by National Aeronautics and Space Administration (NASA), STS-134 Mission Specialist Michael Fincke smiles behind his helmet visor as he participates in the flight's third spacewalk outside the International Space Station (ISS) May 25, 2011 in space. After 20 years, 25 missions and more than 115 million miles in space, NASA space shuttle Endeavour is on its final flight to the International Space Station before being retired and donated to the California Science Center in Los Angeles. Capt. Mark E. Kelly, U.S. Rep. Gabrielle Giffords' (D-AZ) husband, will lead mission STS-134 as it delivers the Express Logistics Carrier-3 (ELC-3) and the Alpha Magnetic Spectrometer (AMS-2) to the International Space Station. (Photo by NASA via Getty Images)

IN SPACE - MAY 16: In this handout provided by National Aeronautics and Space Administration (NASA), Astronaut Mark Kelly, STS-134 commander, gets to work soon after Endeavour reaches Earth orbit as he sits at the commander's station on the shuttle's forward flight deck as he and five other veteran crew members head to the International Space Station May 16, 2011 in space. After 20 years, 25 missions and more than 115 million miles in space, NASA space shuttle Endeavour is on its final flight to the International Space Station before being retired and donated to the California Science Center in Los Angeles. Capt. Mark E. Kelly, U.S. Rep. Gabrielle Giffords' (D-AZ) husband, will lead mission STS-134 as it delivers the Express Logistics Carrier-3 (ELC-3) and the Alpha Magnetic Spectrometer (AMS-2) to the International Space Station. (Photo by NASA via Getty Images)

IN SPACE - MAY 18: In this handout provided by National Aeronautics and Space Administration (NASA), STS-134 and Expedition 27 crew members are pictured in the Harmony node of the International Space Station shortly after space shuttle Endeavour and the space station docked in space and the hatches were opened, from the left are European Space Agency astronaut Roberto Vittori, STS-134 mission specialist; NASA astronaut Mark Kelly, STS-134 commander; Russian cosmonaut Dmitry Kondratyev, Expedition 27 commander; NASA astronaut Cady Coleman, Expedition 27 flight engineer; and NASA astronaut Greg H. Johnson, STS-134 pilot May 18, 2011 in space. After 20 years, 25 missions and more than 115 million miles in space, NASA space shuttle Endeavour is on its final flight to the International Space Station before being retired and donated to the California Science Center in Los Angeles. Capt. Mark E. Kelly, U.S. Rep. Gabrielle Giffords' (D-AZ) husband, will lead mission STS-134 as it delivers the Express Logistics Carrier-3 (ELC-3) and the Alpha Magnetic Spectrometer (AMS-2) to the International Space Station. (Photo by NASA via Getty Images)

IN SPACE - MAY 18: In this handout provided by National Aeronautics and Space Administration (NASA), the International Space Station is featured in this image photographed by an STS-134 crew member at an aft flight deck window of space shuttle Endeavour during rendezvous and docking operations May 18, 2011 in space. After 20 years, 25 missions and more than 115 million miles in space, NASA space shuttle Endeavour is on its final flight to the International Space Station before being retired and donated to the California Science Center in Los Angeles. Capt. Mark E. Kelly, U.S. Rep. Gabrielle Giffords' (D-AZ) husband, will lead mission STS-134 as it delivers the Express Logistics Carrier-3 (ELC-3) and the Alpha Magnetic Spectrometer (AMS-2) to the International Space Station. (Photo by NASA via Getty Images)

IN SPACE - MAY 26: In this handout provided by National Aeronautics and Space Administration (NASA), NASA astronaut Greg Chamitoff during the mission's fourth STS-134 spacewalk outside the International Space Station (ISS) May 26, 2011 in space. During the spacewalk, Chamitoff and fellow astronaut Michael Fincke stowed the 50-foot-long boom and added a power and data grapple fixture to make it the Enhanced International Space Station Boom Assembly, which extends the reach of the space station's robotic arm. The docked space shuttle Endeavour is visible at top right. After 20 years, 25 missions and more than 115 million miles in space, NASA space shuttle Endeavour is on its final flight to the International Space Station before being retired and donated to the California Science Center in Los Angeles. Capt. Mark E. Kelly, U.S. Rep. Gabrielle Giffords' (D-AZ) husband, will lead mission STS-134 as it delivers the Express Logistics Carrier-3 (ELC-3) and the Alpha Magnetic Spectrometer (AMS-2) to the International Space Station. (Photo by NASA via Getty Images)